Welding helmets are generally comprised of a shell with a frontal lens through which a welder views work in progress. A useful improvement to such helmets has been developed. The improvement features a photochromatic lens or shutter assembly. Without the automatic darkening lens, a welder must raise and lower his helmet to view and prepare for welding. The photochromatic lens typically uses an electronic circuit which automatically darkens the lens when a welding flash is detected. A cessation of welding flash or light returns the lens to a lighter shade for viewing. While this feature is valuable in saving eyes, there is an inherent flaw. The darkening of the lens does not occur instantly. The time delay before darkening, although typically a fraction of a second, is still both dangerous to eyes and inconvenient. The present invention solves the problem of delay between the time of welding flash and lens darkening.
1. Field of the Invention
The present invention relates to welding machines and helmets with photochromatic lens and more specifically to a welding flash protection apparatus that provides for darkening of the lens without delay between welding flash and darkening.
2. Description of the Prior Art
Prior related art focuses primarily on the circuitry of photochromatic welding lenses. Such equipment compliments, but does not replace the present invention.
U.S. Pat. No. 6,070,264 issued on Jun. 6, 2000 to Hamilton et al teaches a welding helmet having a darkening and manually adjustable lens shade control. The helmet would benefit from the addition of the present invention in that the present invention prevents delay between the time of welding flash and the darkening of a lens.
U.S. Pat. No. 6,841,772 issued on Jan. 11, 2005 to Hamilton teaches an eye protection device having dual high voltage switching. The present invention would compliment this device by preventing a delay between a welding flash and darkening of a lens.
U.S. Pat. No. 6,844,922 issued on Feb. 15, 2005 to Hamilton teaches lower power phototransistor-based welding providing reduced sensitivity to low intensity light. However, it does not address the issue of a delay between welding flash and lens darkening as does the present device.
Prior art devices can fail if the photosensor lens become blocked out while view of the arc remains clear. This allows for retinal damaging light to penetrate the lens. My device overcomes this problem by allowing the lens to darken independent of the photosensitivity of a given lens.
While the above-described devices fulfill their respective and particular objects and requirements, they do not describe a welding flash protection apparatus that provides for the advantages of the present invention. Therefore, a need exists for an improved welding flash protection apparatus. In this respect, the present invention substantially departs from the conventional concepts and designs of the prior art.